Microsoft Corp will invest $50m in Concentric Networks Inc. The two companies have also agreed to create a co-branded internet portal. Concentric provides high-speed and dial-up internet access and hosting services for small- to medium-sized businesses. Microsoft has extended to 2002 a contract for Concentric to supply network services to Microsoft’s WebTV. Concentric expects to earn $150m to $200m from that contract alone. In return, Concentric will spend $7.5m advertising its IP network services on Microsoft’s internet portal site, MSN. Concentric, which plans to create a co-branded version of MSN for its dialup subscribers, said this portal would be the key to the whole alliance. The companies also plan to develop and co-market Microsoft NT Server-based application hosting services.